With reference to FIG. 7 and FIG. 8, a description is provided for a conventional laser oscillation device described in Patent Literature 1.
FIG. 7 is a schematic view showing the conventional laser oscillation device. As shown in FIG. 7, the conventional laser oscillation device includes discharge tube 101, output coupling mirror 102, total reflection mirror 103, electrodes 104, 105, high-frequency power source 106, cooler 107, gas cylinder 108, valve 109, vacuum pump 110, and turbo blower 120. Laser beams are oscillated by the conventional laser oscillation device in the following manner.
The laser gas in gas cylinder 108 is introduced into the laser oscillation device via valve 109. While being cooled by cooler 107, the laser gas is circulated by turbo blower 120 so as to go through discharge tube 101. Voltages are applied to electrode 104 and electrode 105 by high-frequency power source 106. Thereby, the laser gas is excited in discharge tube 101, and the laser light is oscillated. The oscillated laser light reciprocates between output coupling mirror 102 and total reflection mirror 103. Thereby, the energy of the laser light is increased, and the laser light is output to the outside through output coupling mirror 102.
FIG. 8 is a sectional view showing conventional turbo blower 120. As shown in FIG. 8, conventional turbo blower 120 includes turbo blade 121, rotor 122, stator 123, bearings 124, 125, opening 126, intermediate chamber 127, labyrinth seals 128, 129, discharge tube 130, and valve 131. Conventional turbo blower 120 drives in the following manner.
The shaft supported by bearings 124, 125 and having rotor 122 fixed to the shaft is rotated by stator 123, thereby turbo blade 121 fixed to the tip of the shaft rotates. With this operation, the laser gas above turbo blade 121 is sucked and discharged to the sides of turbo blade 121, thus the laser gas is circulated. At the same time, the gas in intermediate chamber 127 is discharged from discharge tube 130 via valve 131. This operation prevents the oil in bearings 124, 125 from entering the laser gas.